The following description is provided to assist the understanding of the reader. None of the information provided or references cited is admitted to be prior art to the present technology.
The carbon atoms in single-wall carbon nanotubes are arranged in long, hollow cylinders. The carbon nanotubes may also exist as multi-walled nanotubes where a series of smaller tubes are contained within a larger outer shell in a nested, concentric arrangement. The angle at which the sheet of carbon atoms rolls into the nanotube imparts a characteristic “twist” to the structure of carbon nanotubes. This twist is known as the “chirality” of the tube. The chirality can be represented by a chiral vector (n, m) that contains information on both the angle of twist and diameter of the tube. The chirality distribution and the band gap of CNTs can be tuned. Theoretical and experimental observations have confirmed that carbon nanotubes will act as metals or as semi-metals when |n−m|=3q, where q is an integer value. Otherwise, nanotubes behave as semiconductors, with a band gap which is inversely proportional to their diameter.
Chirality can be geometrical as well as topological. The chirality of single-wall nanotubes (SWNTs) and graphene is primarily topological or configurational. On the other hand, the enantiomeric forms commonly observed in simple organic molecules (e.g., L and D amino acids) assume geometrical chirality. The interaction of these two chiral entities has rarely been studied.